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Chemical and magnetic order in platinum-rich Pt + Fe alloys

1963; Royal Society; Volume: 272; Issue: 1350 Linguagem: Inglês

10.1098/rspa.1963.0060

2053-9169

G. E. Bacon, J. Crangle,

Magnetic Properties and Applications

Neutron-diffraction and direct magnetic measurements have been used to determine the magnetic structures of platinum + iron alloys in the neighbourhood of the composition Pt 3 Fe. It is found that the magnetic structure is sensitively dependent on the precise chemical order, in particular on the number of nearest-neighbour iron atoms. Alloys of the stoichiometric composition, where the chemical order is perfect, have a simple antiferromagnetic structure, but addition of excess iron leads to the coexistence of two different structures, with different Néel temperatures but a single, undistorted, cubic unit cell. An incipient ferromagnetic state which shows a cluster type of behaviour is associated with the presence of excess iron. Increase of iron content beyond 34 % leads to the growth of bulk ferromagnetism. Throughout the sequence of structural changes the iron atoms carry a magnetic moment of about 3.3 μ B and there appears to be very little alined moment on the platinum atoms.